Dumb Battery Question

I have been playing active basses for almost 20 years now and I have a stupid question that is bothering me as of late:

....How much, if any does the output signal and/or frequency boost decrease as battery power decreases? If it is a matter of simple voltage does it either work or not work?
...I imagine the type of electronics have something to do with this answer. The only bass I have EVER had absolute battery failure with was equiped with a strait set of active EMG's @18V, other than that I have always just replaced batteries every six months or so and have not really noticed any changes in output. I was also given a pair of battery "jumpers" from my tech, it's a 9Volt battery plug with the + & - wires soldered together so I can run with one or no batteries if need be without breaking output chain as my pups will run in passive mode if needed or desired.
.....any educated thoughts on this?

hmmmm...good question...how does one accurately quantify this without setting up a tone generator feeding a preamp 24/7 until it dies and doing several tests at different levels...

my guess is you can't...

but with that said...we know that having your preamp on all the time (cable plugged in to activate the jack switch on most setups) will definitely kill your battery(s).

It DOES stand to reason that more output will use more batteries, but remember battery usage is about current draw and the current difference is minimal, it is more about signal (voltage) level. So I'd guess the most power used in a battery is from powering the circuit in the first place.

I wasn't aware that you could "jumper" out EMG's...interesting...I have an EMG in my P-copy...so I'm definitely interested...

I wasn't aware that you could "jumper" out EMG's...interesting...I have an EMG in my P-copy...so I'm definitely interested...

please give it a try and let us know the results.

Click to expand...

Sorry for the confusion. The jumpers were given to me for my Dingwall pups, not the EMG's, I mentioned them because the only bass I have ever had an actually battery failure with is EMG equipped. I'm pretty sure the EMG's need juice to function.

I don't know that it's an all or none thing but that's the apparent effect it's had with the actives I've ran. I used to have a wall of active basses (including EMGs) and used rechargeables as a result. I've heard of batteries just going like a light switch like you said. All of mine would start to distort before they would go and I could also tell a volume drop at that point. Before it got to that point, I couldn't tell any difference.

I think bassplayer recommended not letting the battery drop below like 8.3 volts but I'm guessing there's cushion in that. Mine would go down to about 7.5 before distorting.

What you could do if you wanted to know, is rig up a plug so you could check voltage with a meter through your input jack (or just pull the battery and check it). Pick a tune on the CD set to a known volume/tone settings and set your controls on your bass (making note of the settings). Then periodically plug and play to the tune at the same settings and do a voltage check. Keep a chart as it goes down till the battery is done (or just note at what point you need to make adjustments on the bass to keep up with the CD and take a voltage reading).

As long you can play to the same tune at the same CD settings without having to increase volume on the bass or bass tone controls, there's no correlation between battery loss and bass output of any significance.

Pretty bare bones and simplistic and it may not be precise, but it will answer your question - for your bass in particular no less.